<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            width: 100%;
            overflow: hidden;
            background: blue;
            margin: 50px;
            text-align: center;    
        }
        button{
            cursor: pointer;
        }
    </style>
</head>
<body>
    <div>
        <button onclick="alert('单击事件触发')">按钮1</button>
        <button onmouseover="alert('鼠标移入')">按钮2</button>
    </div>
</body>
</html>